Depending on which input sits where on this patch, a music stream (radio, mp3's) can automatically take over from the project mix or vice versa, as suits you best.
Previously I used a ducker/gate combo, since my external player enters via an analog input, but this looks more friendly in the project view and on dsp.
A simple patch but very convenient, this auto-crossfade has become part of most of my projects...
Enjoy
